Despite considerable advancement in the therapy of various tumors and cancers, residual disease is still a major problem in the clinical management of these conditions. Additionally, treatment and especially prevention of infectious diseases remains a continuing concern due to, e.g., spread of viral diseases such as HIV and emergence of treatment-resistant variants of more well known diseases such as tuberculosis, staphylococcus infection, etc.
In the case of tumor treatment, chemotherapeutic strategies are necessarily limited by severe toxicities, and are of limited efficacy against non-proliferating tumor cells. Therefore, new methods emphasizing non-chemotherapeutic approaches are desired. For example, treatment of patients with advanced HER2/neu expressing tumors (e.g., breast cancers) through use of a humanized anti-HER2/neu monoclonal antibody, Trastuzumab (previously known as rhuMAb HER2), directed at the extracellular domain of HER2/neu can lead to a measurable response in some patients with tumors that overexpress the HER2/neu oncoprotein. However, only a subset of patients treated with Trastuzumab show an objective response, and although a combination of Trastuzumab with chemotherapy enhances its anti-tumor activity, still not all patients respond positively. Furthermore, even more desirous than an effective treatment for such tumors would be an effective prevention of them (e.g., especially in individuals with a family history of particular cancers).
Previously, antibody-(IL-2) fusion proteins have been the best characterized and most broadly used in successful anti-tumor experiments using animal models (see, e.g., Penichet and Morrison, 2001, “Antibody-cytokine fusion proteins for the therapy of cancer” J Immunol Met 248:91-101). Numerous studies have explored various combinations of antibodies and, e.g., IL-2, as direct targeting agents of tumor cells. For example, a tumor specific antibody-(IL-2) fusion protein was previously developed by the inventors, and comprised a human IgG3 specific for the idiotype (Id) of the Ig expressed on the surface of the B cell lymphoma 38C13 with human IL-2 fused at the end of the CH3 domain. See, Penichet et al., 1998 “An IgG3-IL-2 fusion protein recognizing a murine B cell lymphoma exhibits effective tumor imaging and antitumor activity” J Interferon Cytokine Res 18:597-607. That antibody fusion protein, IgG3-CH3-(IL-2), was expressed in Sp2/0 and was properly assembled and secreted. Anti-Id IgG3-CH3-(IL-2) has a half-life in mice of approximately 8 hours, which is 17-fold longer than the half-life reported for IL-2 (i.e., when not fused to another domain), and it showed a better localization of subcutaneous tumors in mice than the anti-Id IgG3 by itself. Most importantly, the anti-Id IgG3-CH3-(IL-2) showed enhanced anti-tumor activity compared to the combination of antibody and IL-2 administered together. Again, see, Penichet et al., 1998, supra. Additionally, a chimeric anti-Id IgG1-(IL-2) fusion protein (chS5A8-IL-2) expressed in P3X63Ag8.653 has shown more effectiveness in the in vivo eradication of the 38C13 tumor than the combination of the anti-Id antibody and IL-2 or an antibody-(IL-2) fusion protein with an irrelevant specificity. See, Liu et al., 1998 “Treatment of B-cell lymphoma with chimeric IgG and single-chain Fv antibody-interleukin-2 fusion proteins” Blood 92:21030-12.
Another example of previous antibody fusion proteins in cancer treatment involved chimeric anti-GD2 IgG1-(IL-2) fusion protein (ch14.18-IL-2) produced in Sp2/0 cells. See, Becker et al., 1996 “T cell-mediated eradication of murine metastatic melanoma induced by targeted interleukin 2 therapy” J Exp Med 183:2361-6; Becker et al., 1996 “An antibody-interleukin 2 fusion protein overcomes tumor heterogeneity by induction of a cellular immune response” Proc Natl Acad Sci USA 93:7826-31; and Becker et al., 1996 “Long-lived and transferable tumor immunity in mice after targeted interleukin-2 therapy” J Clin Invest 98:2801-4. The ch14.18-IL-2 treatment of mice which had pulmonary and hepatic metastases, as well as subcutaneous GD2 expressing B16 melanoma, resulted in a specific and strong anti-tumor activity. This anti-tumor activity was significant compared to antibody (ch14.18) and IL-2 or irrelevant antibody-(IL-2) fusion proteins and resulted in the complete eradication of the tumor in a number of animals. See, Becker references, supra. Similar results have been obtained in mice bearing CT26-KSA hepatic and pulmonary metastases and treated with a humanized anti-KSA antibody-IL-2 fusion protein (huKS1/4-IL-2) produced in NS0. See, Xiang et al., 1997 “Elimination of established murine colon carcinoma metastases by antibody-interleukin 2 fusion protein therapy” Cancer Res 57:4948-55 and Xiang et al., 1999 “T cell memory against colon carcinoma is long-lived in the absence of antigen” J Immunol 163:3676-83.
Other examples of antibody fusion molecules include a chimeric anti-human MHC class II IgG1 fused to GMCSF (chCLL-1/GMCSF) expressed in NS0 (see, Hornick et al., 1997 “Chimeric CLL-1 antibody fusion proteins containing granulocyte-macrophage colony-stimulating factor or interleukin-2 with specificity for B-cell malignancies exhibit enhanced effector functions while retaining tumor targeting properties” Blood 89:4437-47) and a humanized anti-HER2/neu IgG3 fused to IL-12 (see, Peng et al., 1999, “A single-chain IL-12 IgG3 antibody fusion protein retains antibody specificity and IL-12 bioactivity and demonstrates antitumor activity” J Immunol 163:250-8), IL-2 (see, Penichet et al., 2001, “A recombinant IgG3-(IL-2) fusion protein for the treatment of human HER2/neu expressing tumors” Human Antibodies 10:43-49) and GMCSF expressed in P3X63Ag8.653 (see, Dela Cruz et al., 2000, “Recombinant anti-human HER2/neu IgG3-(GMCSF) fusion protein retains antigen specificity, cytokine function and demonstrates anti-tumor activity” J Immunol 165:5112-21).
In all of the above work, it is important to note that the antibody-cytokine fusion proteins containing IL-2, IL-12, or GMCSF, etc. have been used as direct antitumor agents which directly targeted tumors in animal models. The antibody fusion proteins bound to antigens on tumor surfaces, thus increasing the local concentration of, e.g., Il-2, etc. around the tumor. The increased, e.g., IL-2, thus lead to anti-tumor activity in some cases. See, e.g., Penichet, et al. 2001, supra.
Additionally, some prior work by the inventors described linking antigens to IL-2 via an IgG3-(IL-2) fusion protein with affinity for a convenient hapten antigen, dansyl (DNS). See, Harvill et al., 1996 “In vivo properties of an IgG3-Il-2 fusion protein. A general strategy for immune potentiation” J Immunol 147:3165-70. The antigen used in this work was highly artificial (bovine serum albumin) rather than a disease-related antigen. Using hapten-conjugated-bovine serum albumin (DNS-BSA) as a model antigen the inventors showed an antibody response elicited by anti-DNS-IgG3-(IL-2)-bound DNS-BSA injected into mice increased over that of DNS-BSA-Sepharose, anti-DNS-IgG3-bound DNS-BSA, or a non-specific IgG3-(IL-2)-bound DNS-BSA. Although, the binding of the antibody-(IL-2) fusion protein to the antigen (non-covalent physical linkage) was shown to enhance the immune response (see, Harvill et al., 1996, supra), only one antibody fusion protein (antibody-(IL-2) fusion protein was used and the study was restricted to the characterization of the humoral (antibody) immune response. Also, unfortunately, use of the dansyl group may create a low level of stability between the antigens and the antibodies. Such instability could be problematic in proper immune stimulation treatments in vivo. Additionally, the use of dansyl, entails the possibility that the dansyl groups could mask or alter specific epitopes on the antigen it is linked to, thus, interfering with proper immune response stimulation in subjects.
In the case of infectious diseases, numerous bacteria (such as Staphylococcus aureus), viruses, mycoplasms, fungi, parasites, etc. present a serious problem. For example, the bacteria Staphylococcus aureus is a common cause of hospital-acquired infections that result in high mortality. Staphylococcus aureus can cause, e.g., pneumonia, endocarditis, osteomyelitis, septic arthritis, postoperative wound infections, septicemia, toxic shock, etc. Unfortunately, many bacterium, including many strains of Staphylococcus aureus, are resistant to first-line drugs such as synthetic penicillins (e.g., methicillin). Other bacteria, including some strains of Staphylococcus aureus, are resistant to multiple drugs, including the so-called antibiotic of last resort, vancomycin. In the case of other infectious agents (e.g., viruses, fungi, etc.) no effective drug treatment may exist. See, e.g., Nickerson et al., 1995 “Mastitis in dairy heifers: initial studies on prevalence and control” J Dairy Sci 78:1607-18; Lowy, 1998 “Staphylococcus aureus infections” N Engl J Med 339:520-32; McKenney et al., 1999 “Broadly protective vaccine for Staphylococcus aureus based on an in vivo-expressed antigen” Science 284:1523-7; and Lorenz et al., 2000 “Human antibody response during sepsis against targets expressed by methicillin resistant Staphylococcus aureus” FEMS Immunol Med Microbiol 29:145-53. The existence of multiple drug resistant strains of bacterium (and, indeed, of other infectious agents such as fungi, mycoplasms, etc.) raises the specter of untreatable infections and presents an ongoing challenge to the medical and public health communities. Much previous work has been done on generation of vaccines (e.g., both DNA and protein vaccines) for numerous infectious organisms (especially viruses) and such work is well known to those skilled in the art.
A welcome addition to the art would be a convenient method of therapeutic and/or prophylactic treatment to potentiate an effective immune response (humoral and/or cellular) against antigens of tumors and infectious diseases. The current invention provides these and other approaches and methods in treatment.